Catalytic converter



Jan. 26, 1965 c FISHER CATALYTIC CONVERTER Filed July 30, 1962 AIDE-2t:

INVENTOR. 62/024 E5 E1 fish E2 conventional mufiier.

United States Patent C) l 3,167,400 CATALYTEC CONVERTER Charles E.Fisher, La Mirada, Calif, assignor to Norris- Thermador Corporation, LosAngeles, Calif., a corporation of California Filed. July 30, 1962, Ser.No. 213,211 4 Claims. (Cl. 23-488) The present invention relates tocatalytic converters employed in internal combustion engine exhaustsystems for catalytically oxidizing previously unoxidized or onlypartially oxidized components of the exhaust gases which are harmfulwhen released into the atmosphere, such as hydrocarbons and carbonmonoxide, and it relates particularly to a novel catalytic converterconstruction which f permits a maximum amount of catalyst to be embodiedwithin the converter, which provides relatively even temperaturedistribution throughout the catalyst bed without damaging hot spotstending to develop, and wherein the parts of the converter are soarranged that bypass channels cannot develop in the catalyst bed throughwhich the exhaust gases would pass untreated, even though a considerablequantity of catalyst material may have been lost due to attrition orother causes.

Although various devices have been proposed for use in vehicles withinternal combustion engine exhaust systems for reducing or eliminatingsmog-forming and other harmful exhaust gas components, such as unburnedor partially burned hydrocarbons and carbon monoxide, the most practicaland efiicient apparatus for accomplishing this appears to be thecatalytic'converter which is employed in the exhaust system as areplacement for the Such a catalytic converter has a catalyst disposedtherein, usually a bed of particulate catalyst material, which promotesoxidation of such previously unburned or only partially burned exhaustcomponents, and this chemical action is exothermic, i.e., produces heat.

However, contemporary vehicles with their relatively limited roadclearance impose structural limitations on catalytic mufilers orconverters, the limitations being such hot spots in the catalyst bed orthe development of bypass channels through the bed, and so as to mosteffective- 1y utilize the catalyst that is present and to avoidlocalized contamination or poisoning of the catalyst by lead compoundsin the exhaust.

It has been found desirable in practice to have the exhaust gases flowvertically, either downwardly or upwardly, through a relatively wide,flat catalyst bed, in order to make the most eflicient use of thecatalyst and to avoid poisoning of the catalyst by lead compounds whichis likely to occur if the exhaust gases flow longitudinally through acatalyst bed of relatively narrow crosssection. However, prior artvertical flow arrangements in catalytic mufliers of generally flattenedform usually resulted in a large waste of the available volume in thecase because of excessively large plenum chambers, so that the amount ofcatalyst employed was seriously restricted.

Another disadvantage of most prior art catalytic mufflers, andparticularly those of the vertical flow type, was

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that heat transfer within the catalyst bed was relatively slow,resulting in delayed activation of the catalyst during engine warm-up,and because of this poor heat transfer and uneven contact of the exhaustgases with various portions of the catalyst bed, hot spots tended todevelop in the catalyst bed, which could cause damage to the catalyst,the muflier case, and possibly surrounding structure of the vehicle.

Further, in many prior art catalytic mufflers, including those of thevertical flow type, it has been found that loss of catalyst due toattrition or other causes provides a bypass or escape paths for theexhaust gases through the muffler Without effective contacting of thecatalyst material.

Accordingly, it is an object of this invention to provide a catalyticmufiler wherein the configuration and dimensions thereof may besubstantially the same as those of conventional mufflers, and thearrangement of the structure of the catalytic mufller provides for theutilization of a maximum quantity of catalyst material.

Another object of the present invention is to provide a catalyticmufller or converter of the character described wherein the partsthereof are so arranged that bypass channels or escape paths cannotdevelop in the catalyst bed through which the exhaust gases can passuntreated, even though a considerable quantity of catalyst material mayhave been lost due to attrition or other causes.

Another object is to provide a catalytic mufiler of the generalcharacter described wherein there is a relatively rapid transfer of heatfrom the input portion of the catalyst bed to the remainder of the bed,thus to accelerate activation of the entire catalyst bed during enginewarmup, and wherein the temperature distribution throughout the catalystbed is maintained relatively uniform during operation and localized hotspots will not tend to develop.

A further object of this invention is to provide a catalytic converterof the aforementioned character wherein there is provided an inletplenum tube for exhaust gases which is partitioned from an outlet plenumtube by a baflle, the tubes normally being substantially surrounded bythe catalyst material and being in close proximity to each other tothereby provide a relatively rapid transfer of heat to the catalystmaterial, and to also provide a relatively uniform temperaturedistribution throughout a major portion of the catalytic converter.

A more specific object of this invention is to provide a catalyticconverter of the aforementioned character wherein even though the inletand outlet plenum tubes are in relatively close proximity to each other,the flow path for the exhaust gases from the inlet plenum tube to theoutlet plenum tube through the catalyst material is relativelyextensive.

A yet further object of this invention is to provide a catalyticconverter of the aforementioned character wherein the exhaust gasespassing through the converter follow a generally vertical flow path.

A serious problem exists in connection with catalytic converters whichis that under certain conditions of engine operation, excessively highconcentrations of unburned materials are produced by the engine andpassed through the exhaust systems, which results in the production ofan excessive amount of heat in the catalytic converter. This excessiveheat production in the catalytic converter can darnage the convertercase, and could even be damaging to adjacent underside parts of thevehicle, such as brakes or the like. Excessive heat in the converterwill also tend to accelerate oxidization of the metal which forms theconverter case, thus further tending to reduce the life of theconverter.

In view of the immediately preceding problem, it is an objectofthisinventio n' to provide-a catalytie-con-t V 'verter of theaforementioned character wherein excessive heat production inthecatalyst material will'result in actuating al'valving; system to makeavailableto the "l'exhaustz gasesf a'ipassage through the converterwhich -Lbypasseslthe. catalyst; until such time as-ihel temperature -;vof ".the. catalyst. returns to acceptable limits. a

lfluntheizobjects;and advantages ofthegpresent'invention rxswill appearduring the course'ofzthe tfollowing-rpartnof the: specification;wherein. the details of construction and 19 mode of Operation of apreferredembodiment; are ?de-' -scribedzwitlrlreference. to; the.accompanying drawings, in '-;iwhich: V l j; V l QFIGURE '1.- is a.longitudinal; :vertical. sectional lview,

into outlet plenum tube 30 -from.where they are discharged: However,flowing of the exhaust gases into plenum tube 28 is dependent on thetemperature of catalystbeds 38 and 40. L I v Mostgif not'all', catalystsemployed in'catalytic converters produce an 'exothermic reaction, whenreacting with exhaust gases; i.'e. heat is produced." As a result ;thereis an acceptable temperature operating range, and when this range isexceededdue to unusually large quantities of combustible materials beingexposed to thecatalyst, damagegto the. catalyst, catalytic converter andvehicle 'ican occur, as. before mentioned. 5 :Wl'len the; temperaturerange .isfiiexceededrj valving I system :58 .ipreventsnthe; flow ofexhaust, gasesintol-inlet p1fenuin tubea28 and instead 1 .'partlyr.in.eleyation,illustratingthe-catalytic converter directs theIeXhaustgasesuthrough .conduit5 2.;thrqugh x:;.togethert with 'a: portionaof thevalving systemjfor con- 'open lbutterfly valve 62, and thence into;outlet; or::dis-

trolling the direction of flow of the exhaust gasesthrough charge,plenum .tube 30. a 1' the lconverterii 1 v *Q @Dis'charge plenumztubeiislindirect linearjialignment FIGUREfZ is aghorizontalxsectional view;partly in with anopening 64 in rear; wall 26 midway between side-elevation,..taken on. irregular line' 212JofFIGURE 1. 29 Walls 22and-adjacent the bottom'wallu20, and communi- 7 Q FIGURES isv'across-sectional view taken 'online .33 catingt with; opening 641s avtubular extension;66; which a of: FIGURE 1, showinggttheinlet plenumatubepartitioned vis rwelded ors t rwi ia torearwall Extenfromtheoutletlplenumiube: and illustrating both Itubes skin-66 is fastenedto an exhaust-.gasndischargepipe 68 g? substantially surrounded bycatalyst material, i V p 1 by "atypical flange connection 170.-.i'IfhLlS, it "may he :Exhaust :gases. rhaving unoxidiz'ed.and? onlyv"partially 25. seen that 'gasesientering discharge plenum: tubez30..from conduit 52 flow directly: out .of'j catalyticzconverter 10 andbypass catalyst beds 38;and"40.

- However, exhaustrgasesqfollowingthe normal'flow path are; received in)inlet plenum 'tube 28,; which isogenerally U -shapedin cr0ss-section'.-The open sideof inlet plenum tube 28 is "closed by top ,walltlin Each.leg .of rinletlplenum oxidized components thereinlare deliveredl-fromanino ternal combustion engine .to catalytic converter- 10 1 through.exhaust pipe 12, .the exhaust. pipe-being fastened to.. catalyticrconverter .19 by atypical flange connection,

14. a. Catalytic :converterll) includes an elongated case 16 3.:.'.v'v-hi'ch.isroval-shaped in crossts'ection; see. FIGURE 3, a:

aandwhich embodiesarelatively. flattopi wall 18; a relalube, 23.111215an outwar yfi g 711116113011 it tivelylafiat; bottom? wall 20, ra pairor substantially semi gwhich l l y fas en in Plenum lube/I23 to case 1.cylindricalsideWalls J22, alfront orforward 4wall-24, PI= 1Y by W ng-,Theayb gh of ;inlet:';plenu1n and-a'rear orback wall 26. i a tube 28is-adjacent to horiz ontalfbafile plate .321,

'Disposedlin;case 16 isia lperforate inletplenum tube f'EXh as flQW y lminl t. lp enumztube. 123 iinto '18. which :is partitioned-from 1aperforate outlet plenum b t ys b 88 1 ;andjsin mfi Width of ba l tube30,.by. ashorizontalbafiieplate32. lBafi'l'e plate 32 pla 324 e tha tterwidt tween t e-l of is supported in case 16 substantially midwaybetween i l P I l b 1 @Xh g v za leirflq red t0 L1OPL18 andtbottdmswall210.b'y..vertical struts33=-and by aswm i-a r zcnt l tw ll as. a fi talrflowjpath in v c'onnec.tion .with. end :wallsl24 and 26. Plenum tubes28 V l tOPaSSVaTQlmd bafile Plate 1324111141 into Outlet Plenum and 30,are in vertical alignmenufand together with baflle b i h h hPF Q 3l iLlhsfl laplate 32; thepIenum; tubes arecoextensivein length with I 0 tsrw t fi i b an ia yw l t q -;case"; 16. lAdditionallygplenumtubes 28:and 30 'are 1 2 F b 'i t U- hm l @IOSSsection,.1..equallysspacedinwardly:from -both sidelwalls-22 so as 5 nv r WhQPPFm ifie s n' 'Qlq fi t y-b ltoverticallyi'partition casel'1'6 into apair oflsubstantially', tom Wall W I lY d l fi t r QIidentical-compartments(Stand36,each of: which hasivQsubstantially-thesame volume as: the other and each of V V Y ,whichisafilled with ;a catalyst material, preferably in M??? tube fl as m. rb fig a ez3?- particulate form,sso as to provide a pair of spacedcatalyst50 T 33 b arsb a lQ il lal li r -shedsl38tandz40,-}whlich-inaybeconsider ed-asingle catalyst r iip "Pl um i i a other" and to '.-'i.bed,-all of,-.which lwill hereinafter be described in more 1ligfflgplatev szithat heat fromllQtnexhaulstggase/s n-;.-extensivedetail; I 1' w l .7 .v t 1 :Eorward wall 24 ofr caselot-encloses" the forward end lfelfredl F Lb i Y Q 3 a d-W1 9i l mlm abt l and lot-compartments 34 and 36, land rear wall-26encloses 552 iileat 5 l l l g and t w s iigml F a ilheirearaend of the .compartme ntsso as to prevent the; i f qg t l tP 3i .i i na b loss of catalystmaterial. Howeven the forwardwall I pauselthgplenum n? a fit lfifl 38 Ihas A a Pair of yerticauyx align-edjjopeningsl L42 :afid and arecoextensive arelativelytuniforrnteniperatnre is a neck 46 which dividesintoupper andllower Exhaust-gases angering Ouflgtor dlssharge Plenumtorn wall 20; preferably by.weldinggand the bightof outleg arelemployedto fasten outlet plenum tube 30 to boti'ng inlet; plenum tube 2311sefficiently vconducted or transa conduits .50 and 5 2, respectively,which are joined at a a common ,wall, 54, the conduits .50 :and 52 beingwelded:

ore otherwisefastened to the, forward wall 24, with upper vconduit 50 incommunication with plenum tube 28 and tube'l30 from catalyst beds-38-iaind40 flowfrom plenum 'tubeifitl through extension tubedandintdldischarge 'pipe 68 where they are discharged ltovtheatmosphere.

lowerlconduit52 in communication with plenum tube 30.

Theflow/of exhaust gases into conduits 50' or 52'is controlled-byaiyalving system 58, which includes abutterfly valve 60 disposed inconduit "50 and a butterfly wvalvefildisposed in conduit 52,valvingsystem 58 being .hereinafterdescribe'd in .moreextensive detail. r

I A feature of particular significanceis'the-novel arrangement ofcatalyst beds 38 and 40; There can be as much as about 50% loss ofcatalyst material due to attrition or other causes, and still theexhaust gases fijowing from inlet plenum tube '28 tooutlet plenumftube30 will be Underznormal temperatureconditions-in the catalyst thoroughlytreated to -oxidize those unoxidiged or only partially oxidizedcomponents of thejexhaust: gases. For instancegthe level of catalystbeds 38 and 4 0 may fail to'approximately the levelof baiiieplate ifaZxfWith the catalystgbeds at this rlevel, exhaust gases must still. flowthrough" the catalyst" material in" order to enter outlet plenum tube30, and with the catalyst beds at this level no bypass or escape pathsare available which would enable the exhaust gases to enter outletplenum tube 30 with- I out being treated. By having the exhaust gasesflow downwardly through the converter rather than upwardly, theparticulate catalyst tends to be packed in the lower part of theconverter case, even if part of the catalyst has been lost, thus furtherinsuring against development of bypass channels through the catalystbeds.

As previously mentioned, valving system 58 is responsible forcontrolling the direction of flow of the exhaust gases. This valvingsystem includes a diaphragm actuator 76 which is supported at theforward end of case 16. Actuator 76 is connected to the intake manifold78 of the engine through vacuum conduit 80, and vacuum conduit 80 has avalve 82 therein which is mounted on case it? of catalytic converter 10.Valve 82 includes a temperature sensing probe 84 which extends intocatalyst bed 38 substantially midway in the flow path of the exhaustgases from inlet plenum tube 28 to outlet plenum tube 30. Therefore,although probe 84 is located to one side of case 16, it is in a positionto obtain an average sampling of the temperature occurring withincatalyst bed 38, and

the temperature of catalyst bed 38 is also representative of thetemperature of catalyst bed 40.

Temperature sensing probe 84 may be any suitable I thermo-mechanicaldevice capable of actuating valve 82,

' the normal operating range or within the normal operating range, thetemperature sensing probe 84 holds valve 82 in its open position so thatthe partial vacuum condition within intake manifold 78 is communicatedthrough vacuum conduit 80 to diaphragm actuator 76, and with valve 82 inthis condition the exhaust gases flow into upper conduit 50 and intoinlet plenum tube 28. However, when the temperature in catalyticconverter it) rises above a predetermined value, sensing probe 84 willcause valve 82 to close, so that the intake manifold 78 does notcommunicate with diaphragm actuator '76 through vacuum conduit 80, andwith valve 82 in this condition the flow of exhaust gases will bediverted through lower conduit 52 and directly into and through outletplenum tube 30. A shaft 86 is slidably connected to diaphragm actuator76, and'connected to a free end of shaft 86 is a linkage system 88 whichis connected to butterfly valves 60 and 62.

Butterfly valve 62 will render conduit 52 closed to exhaust gases andbutterfly valve 60 will render conduit 50 open to exhaust gases when thetemperature of the cat- .alytic converter is below or within theacceptable temperature operating range and valve 82 is open, with theresult that exhaust gases will flow into inlet plenum tube 28, throughcatalyst beds 38 and 40, thence into outlet plenum tube 30 from wherethey flow into discharge pipe 68 and then into the atmosphere. However,when'the temperature of catalyst beds 38 and 40 exceeds thepredetermined operating value, valve 82 will close in response to thetemperature rise which results in diaphragm actuator 7 6 causing shaft86 to actuate the linkage system 88 to cause butterfly valve 60 torender passage 50 closed, and butterfly valve 62 to open passage 52. Theexhaust gases will then enter outlet plenum tube 30 and be dischargedtherefrom in the aforementioned manner.

While the instant invention has been shown and described herein in whatis conceived to be the most praetical and preferred embodiment, it isrecognized that dedetails disclosed herein, but is to be accorded thefull scope of the claims.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

l. A catalytic converter for treating exhaust ingredients produced by aninternal combustion engine, comprising: a case defining a chamber havingopposed ends; an inlet plenum tube having an elongated perforatedportion in said chamber extending substantially from end to end thereof;an outlet plenum tube having an elongated perforated portion in saidchamber and extending substantially from end to end thereof in paralleland overlapping relation to said elongated perforated portion of saidinlet plenum tube and in close proximity thereto; a heat conductivebaffle plate between and parallel to said portions and extendingsubstantially the entire length of said portions, said baffle extendinglaterally a substantial distance beyond the sides of said portions andterminating in opposed edges spaced inwardly from opposite sides of saidchamber; and a bed of particulate catalyst material substantiallyfilling said chamber and encompassing substantially all surfaces of saidportions exposed Within said chamber and said bafile plate wherebyto'define an extended flow path for exhaust gases from said inletportion to said outlet portion, through said material and around saidbaiile while providing a short heat conductive path from the regionadjacent one portion to the region adjacent the other portion throughsaid bafi'le plate.

2. A catalytic converter as defined in claim 1 wherein said plenum tubeportions and said baille plate are in direct heat conductive contactsubstantially throughout their lengths.

3. A catalytic converter as defined in claim 1 wherein said plenum tubeportions and said bafile plate are in direct contact substantiallythroughout their lengths and define a partition across said chamberbetween said opposite sides.

4. A. catalytic converter as defined in claim 1 wherein said chamber isof generally flattened oval shape in transverse cross section, havinggenerally flat top and bottom wall portions; said baflle plate beingpositioned generally centrally between said top and bottom wall portionsand said opposed edges being spaced from said sides a distanee about thesame as the distance between said b-afile plate and said top and bottomwall portions.

References Cited by the Examiner UNITED STATES PATENTS 1,875,024 8/32Kryzanowsky 23-2S8.3 2,488,563 11/49 Sills 23288.3 2,614,647 10/52Bryant 181-57 2,747,976 5/56 Houdry 23-4883 2,785,962 3/57 Ruth23--288.3 2,787,119 4/57 Giambruno 23-288.3 2,898,202 8/59 Houdry et al23288.3 2,928,492 3/60 Nelson 23-288.3 2,991,160 7/61 Claussen 23288.33,024,593 3/62 Houdry 23-288.3 3,050,935 8/62 Eastwood 23288.3 3,054,6649/62 Purse 23288.3 3,083,084 3/63 Raymond 23288.3 3,086,839 ,4/63 Bloch23288.3 3,090,677 5/63 Scheitlin et al. 32 288.3 3,094,394 6/63 lnnes etal 23-288.3 3,097,074 7/63 Johnson 23-2883 FOREIGN PATENTS 448,850 6/36Great Britain.

MGRRIS O. WOLK, Primary Examiner.

GEORGE D. MITCHELL, Examiner.

1. A CATALYTIC CONVERTER FOR TREATING EXHAUST INGREDIENTS PRODUCED BY ANINTERNAL COMBUSTION ENGINE, COMPRISING: A CASE DEFINING A CHAMBER HAVINGOPPOSED ENDS; AN INLET PLENUM TUBE HAVING AN ELONGATED PERFORATEDPORTION IN SAID CHAMBER EXTENDING SUBSTANTIALLY FROM END TO END THEREOF;AN OUTLET PLENUM TUBE HAVING AN ELONGATED PERFORATED PORTION IN SAIDCHAMBER AND EXTENDING SUBSTANTIALLY FROM END TO END THEREOF IN PARALLELAND OVERLAPPING RELATION TO SAID ELONGATED PERFORATED PROTION OF SAIDINLET PLENUM TUBE AND IN CLOSE PROXIMITY THERETO; A HEAT CONDUCTIVEBAFFLE PLATE BETWEEN AND PARALLEL TO SAID PORTIONS AND EXTENDINGSUBSTANTIALLY THE ENTIRE LENGTH OF SAID PORTIONS, SAID BAFFLE EXTENDINGLATERALLY A SUBSTANTIAL DISTANCE BEYOND THE SIDES OF SAID PORTIONS ANDTERMINATING IN OPPOSED EDGES SPACED INWARDLY FROM OPPOSITE SIDES OF SAIDCHAMBER; AND A BED OF PARTICULATE CATALYST MATERIAL SUBSTANTIALLYFILLING SAID CHAMBER AND ENCOMPASSING SUBSTANTIALLY ALL SURFACES OF SAIDPORTIONS EXPOSED WITHIN SAID CHAMBER AND SAID BAFFLE PLATE WHEREBY TODEFINE AN EXTENDED FLOW PATH FOR EXHAUST GASES FROM SAID INLET PORTIONTO SAID OUTLET PORTION, THROUGH SAID MATERIAL AND AROUND SAID BAFFLEWHILE PROVIDING A SHORT HEAT CONDUCTIVE PATH FROM THE REGION ADJACENTONE PORTION TO THE REGION ADJACENT THE OTHER PORTION THROUGH SAID BAFFLEPLATE.